Els van de Vijver

26 Statistics Parameters of test reliability including sensitivity, specificity, likelihood ratios and post-test probabilities with their 95% CIs were calculated with the use of the MedCalc statistical software package for biomedical research, (V.12.1.4). To compare the specificities of the different diagnostic pathways the McNemar test for paired data was used. Student’s t-tests and chi-square tests were used to compare baseline characteristics between groups. All tests were two sided and the level of significance used was a p value < 0.05. Data were analysed in SPSS (version 19.0 for windows). Ethical approval and informed consent This study was exempted from Institutional Review Board approval as it involved the study collection of data generated by routine medical care. The data were collected and recorded by the investigators in such a manner that subjects could not be identified, directly or through identifiers linked to the subjects. RESULTS Between February 2009 and June 2010, 117 children and teenagers were prospectively included in the study. Patient characteristics are presented in Table 1 . Chapter 2